Tongue is one of the most powerful muscle of the body and the movements of tongue are very important in speaking and swallowing or deglutation of food and the movements of tongue are controlled by Intrinsic and Extrinsic muscles.
Action of Intrinsic muscles on movements of tongue:
Superior Logitudnal muscle:
- Action: Shortens the tongue and makes dorsum of the tongue concave
Inferior Longitudnal muscle:
- Action: Shortens the tongue and makes the dorsum of the tongue convex
- Action: Broadens the tongue and Flattens the Tongue
- Action: Narrows the tongue and Elongates the constricted tongue
Action of Extrinsic muscles on movements of tongue:
- Acion: Upper fibers retract the lip, Middle fibers depress the tongue and the lower fibers protrude the tongue
It forms the main bulk o the tongue and it is called the safety muscle of tongue
- Action: Depress the tongue and makes, Dorsum of the tongue is made convex, Hyoglossus muscle also acts by retracting and protruding the tongue.
- Action: It pulls the root or posterior base of the tongue upwards, and thus approximating the palatoglossal arches closing the oropharyngeal isthmus helping in swallowing or deglutation.
- Action: It also helps in swallowing by pulling the upwards and backwards.
Nerve supply to Extrinsic and Intrinsic muscles of tongue:
- Hypoglossal nerve supplies: Genioglossus, Hyoglossus, Stylogossus, Superior longitudnal, Inferior longitudnal muscle, Verticalis, Transverse
- Cranial part of the Accessory nerve through pharyngeal plexus supplies the Palatoglossus muscle.